1. Field of the Invention
The invention relates generally to storage systems and more specifically relates to a monitoring circuit adapted for coupling to a storage controller to sense the status of the operating or failed storage controller.
2. Discussion of Related Art
Present-day storage systems generally include significant processing power for reliable storage management and for high performance. Often, a storage subsystem may comprise a large number of storage devices (e.g., disk drives) with a plurality of high performance storage controllers coupled in a paired redundant fashion to the storage devices and coupled to one or more attached host systems. The controller storage controllers may cooperate in a number of ways to distribute processing load among them to improve performance of the storage system and may be adapted to provide redundancy within the storage system to enhance reliability.
It is also a generally known in the industry that the storage controllers within such high performance, high reliability storage subsystems include substantial monitoring features to evaluate the operating status of the storage subsystem as the storage controller initializes (e.g., “boots”). In other words, an aspect of the initialization process of the storage controllers in such advanced storage subsystems evaluates the health of the storage subsystem as the storage controller is booting. Presuming that the storage controller successfully initializes, anomalies detected in the initialization process may be reported to a cooperating, associated diagnostic application operable within an attached host system or server. An operator may then be notified by the diagnostic application of the anomalous condition to permit operator intervention in resolving the problem.
Despite such operational monitoring during the initialization process, such features may be unusable if the error condition is such that the storage controller is incapable of completing its initialization and boot process. Therefore when such fatal or near fatal errors are present in the storage subsystem there may be no effective means for reporting such a status to an associated diagnostic application to permit operator intervention and thus rapid resolution of the problem.
It is therefore evident from the above discussion that an ongoing need exists for improved diagnostic capabilities what to permit sensing and reporting of such fatal and near fatal anomalies in the operation of a storage controller and/or its associated storage subsystem to thus enable appropriate, rapid remedial actions.